Rearrangements of efferent activity parameters in generators of cyclic motor reactions during electric stimulation of cerebellum inputs and outputs in the cat]

Rearrangements of the activity parameters of scratching and locomotor generators conditioned by electric stimulation of the inferior olive, nucleus reticularis lateralis as well as of the fastigial nucleus and nucleus interpositus of the cerebellum were investigated on decerebrate immobilized animals. Scratching and locomotor generators were characterized by the ability to effectively rearrange the time structure of their activity in response to certain changes in phase and amplitude characteristics of signals arriving both by the mossy and climbing inputs of the cerebellum. The flexor half-centre of the locomotor generator and aiming half-centre of the scratching generator increased both the period and intensity of their activity under influence of signals arriving to the cerebellum from the inferior olive and nucleus reticularis lateralis at the first half of the working phase of these half-centres. Stimulation of the inferior olive and nucleus reticularis lateralis during the second half of the flexor and aiming phases evoked somewhat different changes in correlation of activity for half-centres of the locomotor and scratching generators. A slight shortening of the activity period of the aiming half-centre during scratching and a decrease of the activity period of the extensor half-centre during locomotion were observed. Stimulation of the structures mentioned above during the working phase of half-centres controlling limb extensor movements evoked shortening of the extensor half-centres activity period during locomotion and exerted no effect on the scratching jerk half-centre activity period during scratching. The scratching generator, unlike the locomotor generator is characterized by a significant degree of resemblance of the rearrangement of generator efferent activity parameters evoked by electric stimulation of the cerebellum nuclei and its afferent inputs. Possible mechanisms of forming the correcting influences on scratching and locomotor generators from the cerebellum during changes in phase and amplitude characteristics of its input signals are discussed.